Previously, in connection with the use of quick change tool holders and spindle adapters adapted for securing into a power spindle and including a collet holder shank adapted to receive a collet and a tool, the tool normally extends axially into the body of the quick change tool holder and into operative engagement with a positive drive therein. Previously, the positive drive, normally in operative engagement with the inner end of the tool is adapted for longitudinal adjustments within the body of the tool holder by application of a tool or a screw driver to one end of the positive drive for rotating the positive drive which threadedly engages an internal bore of the body for advancing or retracting the positive drive longitudinally. In order to effect such longitudinal adjustments of the positive drive, it is necessary that the quick change tool holder be removed from the spindle and its axial bore be accessible to a tool such as a screw driver or other tool for rotating the positive drive. This adjusts the position of the tool inwardly and outwardly of the tool holder.